The present invention relates in general to data storage systems such as disk drives, and it particularly relates to a thin film read/write head for use in such data storage systems. More specifically, the present invention relates to a thin film, inductive-type advanced read/write head with a single layer coil and an improved method of fabricating a center tab of the single layer coil.
In a conventional magnetic storage system, a thin film magnetic head includes an inductive read/write element mounted on a slider. The magnetic head is coupled to a rotary actuator magnet and a voice coil assembly by a suspension and an actuator arm positioned over a surface of a spinning magnetic disk. In operation, a lift force is generated by the aerodynamic interaction between the magnetic head and the spinning magnetic disk. The lift force is opposed by equal and opposite spring forces applied by the suspension such that a predetermined flying height is maintained over a full radial stroke of the rotary actuator assembly above the surface of the spinning magnetic disk.
An exemplary magnetic head includes a thin film write head with a bottom pole (P1) and a top pole (P2). The poles P1 and P2 have a pole tip height dimension commonly referred to as xe2x80x9cthroat heightxe2x80x9d. In a finished write head, the throat height is measured between an air bearing surface (xe2x80x9cABSxe2x80x9d), formed by lapping and polishing the pole tip, and a zero throat level where the pole tip of the write head transitions to a back region. A pole tip region is defined as the region between the ABS and the zero throat level. Each of the poles P1 and P2 has a pole tip located in the pole tip region. The tip regions of the poles P1 and P2 are separated by a magnetic recording gap, which is a thin layer of insulation material.
In conventional head designs, as illustrated by FIG. 4, a center tab 2 is formed typically after the main coil body 3, the insulating layer 4, and the P2 pole have been formed. As a result, the coil resistance and inductance of the write head cannot be readily monitored once the coil fabrication is completed.
In conventional head designs, a limited number of coil test sites (dummy coils) are available for probing following the fabrication of the coil main body. In which case, only the coil resistance can be measured because the dummy coil structure does not represent the real coil. Such a test is inaccurate as it leaves the coil yield largely unknown until the final probing test which is implemented at around the end of the wafer processing. Thus, it is difficult to monitor and to improve the coil yield, which is critical for the write head performance.
Furthermore, in conventional designs the center tab process requires several wafer processing steps such as target window seed removal (photolithography and wet etch), center tab fabrication (photolithography, plating, and wet etch of seed), and so forth.
While attempts have been made, though not completely satisfactorily, to alleviate the two former concerns, as exemplified by U.S. Pat. No. 5,649,351 to Wade et al., which is incorporated herein by reference, the concerns associated with the fabrication of the center tab of the single layer coil have not been adequately addressed.
One aspect of the present invention is to satisfy the long felt, and still unsatisfied need for a thin film read/write head with a single layer coil, and an improved fabrication process of the center tab of the single layer coil that reduces the complexity of the wafer processing, which would result in a shorter cycle time as demanded by the need for a faster design-to-market cycle.
According to the present invention, the center tab is formed prior to the fabrication of the coil main body, the insulating layer, and the pole P2. This new fabrication method increases the manufacturing yield and eliminates several wafer processing steps, thereby significantly reducing the cycle time of wafer processing.